// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)

#pragma once

#include <chrono>
#include <ctime>
#include <memory>

#include <string>
#include <vector>
#include <unordered_map>
#include "abel/log/common.h"
#include "abel/log/details/log_msg.h"
#include "abel/log/details/os.h"
#include "abel/log/formatter.h"
#include "abel/memory/memory.h"

namespace abel {
namespace details {

// padding information.
struct padding_info {
    enum pad_side {
        left,
        right,
        center
    };

    padding_info() = default;

    padding_info(size_t width, padding_info::pad_side side, bool truncate)
            : width_(width), side_(side), truncate_(truncate), enabled_(true) {}

    bool enabled() const {
        return enabled_;
    }

    size_t width_ = 0;
    pad_side side_ = left;
    bool truncate_ = false;
    bool enabled_ = false;
};

class ABEL_API flag_formatter {
  public:
    explicit flag_formatter(padding_info padinfo)
            : padinfo_(padinfo) {}

    flag_formatter() = default;

    virtual ~flag_formatter() = default;

    virtual void format(const details::log_msg &msg, const std::tm &tm_time, memory_buf_t &dest) = 0;

  protected:
    padding_info padinfo_;
};

} // namespace details

class ABEL_API custom_flag_formatter : public details::flag_formatter {
  public:
    virtual std::unique_ptr<custom_flag_formatter> clone() const = 0;

    void set_padding_info(details::padding_info padding) {
        flag_formatter::padinfo_ = padding;
    }
};

class ABEL_API pattern_formatter final : public log_formatter {
  public:
    using custom_flags = std::unordered_map<char, std::unique_ptr<custom_flag_formatter>>;

    explicit pattern_formatter(std::string pattern, pattern_time_type time_type = pattern_time_type::local,
                               std::string eol = abel::details::os::default_eol,
                               custom_flags custom_user_flags = custom_flags());

    // use default pattern is not given
    explicit pattern_formatter(pattern_time_type time_type = pattern_time_type::local,
                               std::string eol = abel::details::os::default_eol);

    pattern_formatter(const pattern_formatter &other) = delete;

    pattern_formatter &operator=(const pattern_formatter &other) = delete;

    std::unique_ptr<log_formatter> clone() const override;

    void format(const details::log_msg &msg, memory_buf_t &dest) override;

    template<typename T, typename... Args>
    pattern_formatter &add_flag(char flag, const Args &... args) {
        custom_handlers_[flag] = abel::make_unique<T>(args...);
        return *this;
    }

    void set_pattern(std::string pattern);

  private:
    std::string pattern_;
    std::string eol_;
    pattern_time_type pattern_time_type_;
    std::tm cached_tm_;
    std::chrono::seconds last_log_secs_;
    std::vector<std::unique_ptr<details::flag_formatter>> formatters_;
    custom_flags custom_handlers_;

    std::tm get_time_(const details::log_msg &msg);

    template<typename Padder>
    void handle_flag_(char flag, details::padding_info padding);

    // Extract given pad spec (e.g. %8X)
    // Advance the given it pass the end of the padding spec found (if any)
    // Return padding.
    static details::padding_info handle_padspec_(std::string::const_iterator &it, std::string::const_iterator end);

    void compile_pattern_(const std::string &pattern);
};
}  // namespace abel

#include "abel/log/pattern_formatter_inl.h"
